factchk

name: factchkdescription: "Verify reality-grounded claims against external sources in both directions before they ship: could the 'absurd' be real, could the 'obvious' be false or long-established? Use whenever an artifact, or the sentence you are about to write, asserts something as plausible, realistic, absurd, novel, or impossible from intuition rather than a checked source; before relying on a factual claim in prose, a design rationale, a research claim, or a plan. Fires on metacognitive doubt: when you can't actually know, verify instead of trusting the feeling. Scans read-only, then fixes the clear errors or flags the judgment calls; leaves deliberate fiction alone."

Check claims against reality in both directions before they ship.

Goal

The author's judgment of what is plausible, absurd, or novel is the least reliable line in an artifact. Human priors fail both ways: they exclude the real (desert frogs exist) and normalize the impossible (weightless crates). factchk checks reality-grounded claims against external sources, then fixes errors or flags judgment calls. It checks claims about the world, not the soundness of a validation or the survival of a whole plan.

Workflow

1. Scan for reality-grounded assertions that call something plausible, realistic, absurd, novel, or impossible because of a factual premise. Include claims you are about to write.
2. Verify each against external sources (web search, open references) in both directions: could the "absurd" be real? Could the "obvious" or "novel" be false or long-established? If you cannot reach a source, flag it; never assert from intuition.
3. Fix or flag: correct mechanically clear errors, such as wrong dates, misattributed sources, or falsified numbers, with a cited source. Surface contested or interpretive claims as judgment calls; do not silently rewrite them.
4. Report each claim, its verdict, the source, and which direction a failed claim failed.

Rules

• Target claims asserted as reality-grounded, never deliberate fiction ("in our world, boxes float" is a declared choice). If it is unclear whether a claim is an in-world choice or a real-world assertion, flag, don't fix.
• Flagging only the unrealistic catches half the errors.
• A claim about a person (a title, a past role, a school, an age) is read from that person's own profile or record, and where the source allows two values the artifact states the one that cannot overstate, such as the younger age when a birthday is unknown.
• Metacognitive doubt triggers the check. You cannot know every domain; when you are about to assert a checkable fact from a feeling, verify it.
• A pass that finds nothing changes nothing.

Verification

Before finishing, confirm that every verdict traces to a citable external source. The report distinguishes fixes from flags; it does not restate prior intuitions.